You do realize that when it's out of beta, they could easily drop the beta chain and start a brand new one, right? And that the methodology for someone adding their public key as well as the blockchain node application (wallet) would be open source, so that anyone can look at the code? And that Proton isn't adding your public key to the chain, you are? And that being a beta blockchain kind of necessaily depends on having many nodes, in order to test scalability?
You're out of your depth here, and I'm not going to bother explaining any further.